Multifamily Passive House Certification: A New Reach Standard for Vermont?
Efficiency standards for multifamily new construction (MFNC) in Vermont have evolved significantly over the last two decades, and Efficiency Vermont’s involvement in high-performance standards (and related incentives) for these structures has also advanced. State energy codes have also improved and are on a trajectory toward net-zero-ready requirements for new homes by 2030. Improving energy codes diminishes available energy savings for MFNC programs. As Efficiency Vermont’s High-Performance Standard (EVTHP) for MFNC continues to evolve, it approaches the level of the Passive House (PH) standard in attributes like balanced ventilation, continuous thermal barriers, and increased airtightness. In this whitepaper, Efficiency Vermont researchers studied 10 multifamily projects and evaluated real-world building data to investigate energy performance and cost impacts. They found PH projects show an average of 19% lower operational energy use when compared to EVTHP buildings. Other PH benefits include design flexibility, optimized and integrated building systems, independent review of design and construction, modeled predicted energy use, and a higher level of reliable energy savings. Researchers described the added cost and complexity for PH design, construction, and verification. They also noted that the available incentives may help cover much of the incremental costs, while other stakeholders called for additional incentives to support PH certification. The paper recommends that Efficiency Vermont consider supporting Passive House certification as a new “reach goal” for MFNC projects, alongside the existing EVTHP program. Doing so could accelerate market transformation and cultivate broader workforce alignment with high-performance standards regardless of the standard sought.